A lost concrete shielding container for the retention, storage and disposal of liquid radioactive wastes for a nuclear plant generating electric power is known. The container comprises a vessel having unitary walls and a floor. A lid sealingly closes an open mouth of the vessel and, like the walls and the floor, can be composed of concrete. The container can be filled with radioactive waste which can be mixed with cement or concrete can be poured into the partly filled container to seal the latter. A shield container of this type generally stores the radioactive waste without reduction of volume by vacuum or heating.
It is also known to transport and store spent fuel elements in cast iron or steel containers having a wall thickness of at least about 40 centimeters and sufficient, therefore, to provide a substantial shield effect. Generally these containers have heat exchange ribs and are closed by a casting of the same metal as forms the remainder of the container. Such containers have the advantage that they can be used to treat the waste, e.g. by heating them while exhausting vapors generated in them by the heat. In this manner wet but somewhat solid matter filtered from the cooling circuits of a nuclear-power plant can be dried out for permanent disposal in such containers.